Electric regulation



Aug; 22.1939. w. GoDsEY, lR 2,170,193

ELECTRIC REGULATION Original Filed Jan. 21, 1935 lNVENfOR I Frank W godsey, J1:

BY @M, "I A ATTORNEYS Patented Aug. 22, 1939 PATENT OFFICE Emcmc REGULATION Frank W. Godsey, Jr.,'North Adams, Mass., as-

signor to The Safety Car Heating-8; Lighting Company, a corporation of New Jersey 4 Original application January 21, 1935, Serial No.

2,707, now Patent No. 2,067,604,

dated January Divided and this application December 17, 1936, Serial No- 116,285

3 Claims.

This invention relates to electric regulation.

One of the objects of this invention is to provide a simple, practical and inexpensive regulating system and apparatus that will be of efficient and reliable action and capable of premelon and accuracy of regulation throughout the peculiarly varying conditions of practical use, particularly variations in temperature. An other object is to provide a system and apparatus for the regulation of electrical circuits that will be of wide adaptability and use in successfully coping with the heretofore unsurmounted difliculties caused by changes in temperature. Another object is toprovide an electromagnetic control apparatus for a system or electrical apparatus that will maintain dependably and efilciently the desired or intended standard of operation or control thereof in spite of changes in resistance of the electromagnetic winding due to temperature changes, and to provide such a control system or apparatus capable of a wide range of use in the electrical arts. Another ob- Ject is to provide a system or apparatus of the above mentioned character in which the efliciency is vastly improved, energy consumption diminished, and genuine precision of action achieved. Another object is to provide a system or apparatus of the above mentioned character that will be of simple and inexpensive construction, capable of ready and convienient installation, and compact and rugged in construction. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combination of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be in dicated in the following claims.

This application is a division of my copending application, Serial Number 2,707, filed January 21, 1935, patented January 12, 1937, No. 2,067,604. In the accompanying drawing, in which are shown several of the various possible embodiments of certain mechanical features of my invention, Figure 1 is a diagrammatic representation of one form of regulating apparatus" and system, part of the former being shown in cross-section;

Figure 2 is a vertical sectional view of the resistance unit with the heatinsulation removed;

, and

Figure 3 is a vertical sectional view of the resistance unit with the heat transfer fins removed.

Similar reference characters refer to similar parts throughout the several views in'the draw s.

As conducive to a clearer understanding of certain features of my invention it might at this point he noted that in the electrical arts, particularly in the field of, for example, regulation of electric circuits for constancy of voltage, reliance has to be placed upon an electromagnetic winding in'the-form of a coil or helix, an electromagnet with an armature controlled thereby, or a solenoid winding with a core controlled thereby; in such an electromagnetic winding, of which examples have just been noted purely byway of illustration, the conductor, usually copper wire, of which the winding is made, is subject to variations in temperature due to electrical heat losses in the resistance of the conductor it'- self. The electrical energy dissipated in the form of heat in the conductor is proportional to the product of the square of the current by the resistance of the conductor itself. With change in temperature, the resistance of the conductor and hence of the winding also changes. The

temperature, and hence the resistance, of the conductor making up the winding is thus subject to relatively great changes, being further affected by such variables and factors as the temperature of the atmosphere, the temperature of the apparatus with which the winding may be closely associated physically, the rate of heat dissipation by the winding, the length of the periods of energization of the winding as compared with the length of the periods when the winding is de-energized, and other factors.

If therefore the winding is intended to control, through its magnetic induced flux, any related apparatus mechanisms, circuits, or the like, the production of a critical value of flux must be dependent upon achievement of a fixed or critical value of current through the coil, but due to the variability of the resistance of the winding as above pointed out, the voltage necessary. to achieve this given value of current from the winding will necessarily vary with the variations in the resistance.

Let it be assumed, for example, that the winding is to achieve, with related means, constancy of .voltage in an electrical circuit; if the winding and its related-parts are so constructed as to regulate for constancy of current (to produce the above mentioned flux), the voltage necessary to maintain this constancy of current through the winding varies with the change in resistance of the conductor of the winding, assuming that the winding is bridged directly across the circuit the voltage of which is to be maintained constant.

The result is that very sumtantial departures from the desired value of voltage are caused by the change in the resistance of the winding.

It has heretofore been proposed to counteract these efiects by placing in series with the winding a relatively large external resistance of zero temperature coemcient of resistance and such an. arrangement has become wide practice; the theory of such-practice is that, by thus greatly increasing the total resistance of the winding circuit, the change in resistance that takes place within the winding itself becomes a small enough factor relative to the total circuit resistance to.

tolerate .the nevertheless'inescapable fact of change in voltage of regulation. However, such an arrangement does not remedythe difficulty and is moreover of limited scope of application, not to mention'its wastefulness of material and electrical energy or low efficiency. Where the energy. requirements of the winding or controlling coil are relatively large, the applicability of this'prior' practice fails unless many disadvantagescan still be tolerated.

For example, let it be assumed that the control winding has to be constructed so large that its energy requirement is 100 watts; if the change in resistance of such a winding causes a 15% voltage variation and if it is desired to reduce'that variation to a maximum of 5%, it is necessary to have connected in series with the winding an external resistance which is twice that of the winding, the external resistance requiring therefore that an additional 200 watts must be dissipated therein. If the range of change of temperature of the control winding is still greater, with the corresponding change in resistance,.then

, even larger values of external resistance must be used'to reduce the intimate voltage variation. 7

These instances illustratesome of the distinct disadvantages of such prior practice which, in no case, it will be seen, achieve an entire absence of voltage variation; If the winding therefore is employed for regualtion of voltage, constancy of voltage cannot be and is not achieved.

One of the dominant aims of this invention is to do away with such disadvantages as have Just above mentioned; by way of illustration and to clarify a ready understanding of my invention, I have shown the winding Hi as the control or regulating winding in a'system or apparatus for achieving constancy of voltage across the circuit li-iZ, winding ill being connected, as more clearly hereinafter described, topbe responsive to that function (voltage, in this instance) of the electrical energy in the circuit iii- 42 which it is desiredto maintain constant.

- In so far as certain features of my invention are concerned, the winding l0 may control, af-

fect, or actuate or coact with any desired or suitable parts or apparatus which are, by the winding i0, made to effect a correction of departures from the selected value of the function of the electrical energy that it is desired to maintain constant. For example, the winding ifl may be in the form of a relay for controlling a resistance which in turn is made to affect the voltage across the circuit H-l2; thus for example, a generator is (either alternating current or direct current) v may be the source of supply of electrical energy to the circuit ill2rand the resistance, illustratively in the form of a carbon pile 54, may, un-

der the control of the winding l0, affect the excitation of the field winding 15 of the generator l3, thus to control the voltage of the output of the electrical source i3.

By way of further illustration, the winding It may form part of a solenoid having a fixed core i5 and a coacting movable core l'l, these, two parts being suitably shaped, as bytapering thein as is indicated in Figure 1, so that, with respect to the mechanical resistance opposing movement of the movable core H, the winding It), at a given or intended energization, will hold the core H in whatever position it is moved throughout its range of movement. Movable core ll may be connected to a bell crank lever ll pivoted at is, and having its one arm l8a operating upon the free or unanchored end of the carbon pile M. A spring 20 opposes the pulling effort of'the solenoid. 1

Disregarding resistance changes inure winding I0, increase in voltage across the circuit I l llincreases the energization of the winding l0 beyond the value corresponding to the voltage desired to be maintained constant across the cir-' cuit H--l2, whereupon the pre e on the carbon pile i4 is lessened, its resistance increased, and the resultant decrease in the excitation of the generator l3 restores the voltage to normal.

Should the voltage decrease, a reverse action takes place in that the corresponding decreased energization of the winding is disturbs the mechanical equilibrium theretofore existing and permits the spring 2d to swingi the lever l8 in clockwise direction, thus increasing the pressure on the carbon pile id and correspondingly increasing the excitation of the generator i3 to restore its voltage to normal.

As pointed out above, where the winding i9 is to respond to changes in voltage, it is bridged across the circuit the voltage of which is to he afiected. Accordingly one terminal of winding it is connected by conductor 2i to one side, conductor ii, of the circuit 58-42; the other terminal of winding iii is connected by conductors 22 and 23 to the other side, conductor 52, of this circuit, but through a temperature-change compensating device generally indicated at R.

The device R includes a member 23 having a negative temperature coeiiicient of resistance and has thermally related to it means giving the part 2% a thermal capacity which is high compared to the thermal capacity of the part 24 itself. The winding iii may be constructed in any suitable manner; whatever its physical construction, it

embodies necessarily the mass of conductor (usually copper) of which it is wound together with such possible related parts as an iron core, parts either of solid dielectric material or of metal between which or upon which the conductor is wound, and like parts, giving the winding an ultimate mass having a certain area of exposed surheat-radiating or heat-dissipating surfaces. Depending upon such factors as these, varying as they do with the design, purpose, power or physical dimensions of the winding, the winding is found to have a thermal capacity which is, relatively speaking, large, and it is found that the winding has a corresponding characteristic of face or surfaces which can and do function as I ,ma'terially affected by PR losses therein.

rate of rise of temperature beginning with the flow therethrough of its rated energizing current and hence also a corresponding characteristic of rate of decrease of temperature when the energizing current is cut off. The relatively large ratio of thermal capacity of the coil to cooling surface area of the coil makes this rate of change of temperature relatively low.

The device R (Figure l) embodying a relatively small part 24 (inherently of small thermal capacity) has thermally related to it one or more members, illustratively two in number as shown at 25 and 26 in Figure 1, of a material like cast iron, steel, brass, or other suitable metal or material, in sufficient volume or mass to give the device R, with respect to the latter's heat-radiating surfaces, a high thermal capacity, and moreover a ratio of thermal capacity to heat-radie ating surface of device R that is equal to or commensurate with the ratio of the thermal capacity of thewinding III to the heat-radiating surface of the winding l0,

By way of illustration the part 24, having a negative temperature coefficient of resistance and made of any suitable material having such a coefficient, such as carbon, carbon compositions, psilomelane, galena, silicon-carbide, zincite,

graphite, certain alloys (such as bronze made up of 88% of copper and 12% of tin with a small quantity of phosphorous) may be in the form of a disk interposed between the ends of the parts 25 and 25 which are made up in the form of preferably cylinders made, for example, of cast iron.

Parts 25 and 25 are provided with removable heat-radiating fins 21- and are recessed at 28 and 29. They are also provided with removable wrappers of heat-resisting and heat-insulating material 30. By removing the fins and leaving all, or part, of the insulating material in place, heat-radiation is cut down. By removing the insulating material and leaving all, or part, of the fins in place, heat-radiation is increased. By leaving a suitable .number of fins and a suitable amount of insulation in place, it is possible to du- Y plicate the heat characteristics of electrical units,

such as solenoid with an iron core, which characteristics cannot easily be duplicated without the use of both fins and insulating material. -Thus, the fins and the insulating material act together to form a control means, whereby it ispo'ssible to control the heat characteristics of the unit to make them correspond to the corresponding characteristics of an electrical unit.

The members 25-25 may or may not be included in the circuit of the winding Ill though it is more convenient to include them in that they may thus also serve as the contactors with the disk-like resistance element 24; the cross-section of metal in the members 2525 is sufficiently large virtually in any case so as not materially toaffect the resistance of the circuitor to be In any event the resistor 24, ofnegative temperature coefficient and of small mass and hence of small thermal capacity is in the circuit of the windng l and has its thermal capacity greatly increased by being thermally related to a relatively large mass such as the metal members 25-26. As the resistor 24 heats up, due to the flow of current therethrough, heat flows from the resistor 24 to resistor 24 substantially matches or equals the rate of change of temperature of the winding l0. Depending upon the relative temperature coefficients of resistance and upon the relative ohmic resistances of the winding l0 and the resistor 24, the mass of the part or parts 25-26 and the heatdissipating surfaces thereof may be changed or determined to control the rise or fall of temperature of the resistor 24 with continued flow of current or cessation thereof respectively sothat the increment of change of resistance in winding ll in one direction is exactly counterbalanced by an equal increment of change in resistance in the resistor 24 in the opposite direction.

. With this arrangement exact or precise regulation at the intended voltage may be accomplished. This regulation is effective 'over a wide range of temperature and voltage and over a long period of time. Due to the fact that parts 25 and 25 absorb and dissipate heat along the same curves as does coil l0 and its associated parts, the respective temperatures of resistor 24 and coil II will be substantially identical at all times; there will be no lag of one temperature with respect to another regardless of the rapidity of fluctuation of the line voltage and the temperature of the surrounding atmosphere.

As pointed out above, in obtaining this result it is at times necessary to provide fins which perform the function of carrying heat away rapidly, and act in the manner that flanges upon an iron core might act. With such fins in place it might be necessary to add a suitable amount of heatinsulating material 35, to correspond to the heatinsulating material associated with coil II. In a likemanner, recesses 28 and 29, or any other deformation, might be provided to correspond with recesses or other deformations in core II. It is understood that these various means may be used either separately or together, but that by providing a choice of these three means, a complete control of heat characteristics of the resistance unit is provided.

Figure 2 shows the resistance unit of Figure 1 with all of the heat-insulating material removed so as to give maximum effective heat-radiating surface; and Figure 3 shows the same unit with the fins removed but with the heat-insulating material in place so as to give minimum effective heat-radiating surface. This illustrates the wide range of operating characteristics which may be obtained from a single resistance unit, although it is understood that additional fins might be provided in Figure 2 and additional insulating material might be provided in Figure 3.

I have above mentioned, by way of illustration, certain specific examples of materials which may be employed in my system and apparatus and which have a suitable negative temperature coefilcient of resistance. Now in accordance with certain other features of my invention, I may employ for the material of. the resistance medium, such as the resistor 24, material having the characteristic of changing its ohmic resistance with change in voltage applied to the resistance material itself.

Such materials which substantially depart from Ohms law in that the current flowing in the circuit is not necessarily proportional to the voltage impressed are known as non-linear impedances, and may take the form of inductances with iron cores, thermionic vacuum tube conductors, gaseous discharge devices such as neon lamp or helium glow lamps, certain electrolytic conductors and manyother devices. Some devices are pure resistance devices and follow Ohms law for direct current, such as an iron-' cored inductancawhile on alternating current, the impedance of the device or its resistance to current flow, is dependent upon the impressed voltage and other factors, such as the frequency of alternating voltage. Other materials have a practically instantaneous response to voltage variations, so that the characteristics do not depend upon its immediately previous history, and

be the case if current were always proportional to the voltage impressed. Thus, in a pure resistance with a linear impedance characteristic, the current will be proportional to the impressed voltage.

, '-With a non-linear impedance material used for the resistance unit, the current may not be proportional to the voltage, as the current in creases much more rapidly than voltage. Thus, if in a regulating system a definite current change must be made in the current of energization of winding it! (Figure 1) in order to overcome mechanical friction and magnetic hysteresis to achieve a desired change, the change in voltage for. a pure linear impedance will require the. same percent variation in regulated voltage to achieve the required current change as is the magnitude of the current change in percent of total current flowing in winding Hi. However, if a non-linear impedance material is used as the resistance element in the coil circuit of winding ill, then it is' readily apparent that a small voltage variation will result in a relatively large change in current in winding ill in its at tendant non-linear resistance unit. Therefore, to obtain a required current change in winding ill, the change in regulated voltage will be much less if a materialis used having a non-linear impedance characteristic rather than a linear impedance.

In alternating current circuits, such an efiect is obtainable very readily by placing an ironcored inductance in series with the winding 60, so proportioning the core in the inductance coils that the iron is near or beyond its saturation value at the voltage 'at which the system is to regulate.

In both alternating and direct current circuits, materials which have a practically instantaneous response to voltage variations are of advantage due to their independence of the frequency of the system voltage, whether alternating or direct current.

One such material is commercially known as Thyrite; U. S. Patent No. 1,822,742 and is obtainable from the General Electric Company at Schenectady, N. Y.; this material, described in the General Electric Review of February, 1930, has mechanical characteristics somewhat similar to those of dry-process porcelain and has the characteristic that its conductivity varied with the potential. For example, the ohmic resistance is equal to aco'nstant (which depends upon the physical dimensions of the material to be employed) divided by the current to the exponential a, as set forth in the above-mentioned publication. To illustrate the action of this material, it

might be noted that its above-mentioned proper- .ties are of such a character that doubling the voltage results in a. flow of current therethrough the magnitude of which is on the order of twelve times the magnitude of the current flowing before the voltage was doubled. Thus, the resistor 26 may be in the form of a disk of Thyrite,

illustratively a disk or annulus of about three inches in diameter. and about one-eighth of an inch in thickness. This material, moreover, also has a negative temperature coefflcient of resistance in that its resistance decreases with increase in temperature.

In addition to the advantages resulting from the use of a resistor with a negative temperaturecoeficient of resistance, a resistor made up of this material such as Thyrite achieves many marked advantages. Illustratively let it be assumed ,that the winding H] has the following characteristics, namely, a resistance on the order of 100 ohms, an operating voltage on the order of 50 volts, and an operating current or a critical current of energization of 0.5 ampere let it be assumed, also, that, in accordance with the past practice as hereinabove earlier mentioned, there is included in the circuit of this winding an external resistor of 200 ohms, so that at 0.5 ampere, the voltage drop across the resistance is 100 volts; A variation of 3% in the current of energization due perhaps'to any condition of electromechanical unbalance ii'i aregulating or relay system would result in a variation of 1.5 volts across the winding and of 3.0 volts across the resistance making a total voltage variation to which the system and apparatus is subjected of 4.5 volts.

If, however, instead of using such a resistance in accordance with prior practice, I use a resistor oi 'I'hyrite in circuit with the above-assumed winding such that the above-mentioned 3% voltage variation (increase in voltage drop across the winding l due to 'the increase in current of energization) is effective, due to the abovedescribed characteristic of the material, to produce a voltage drop across the resistance of only 0.25 volt, then the total voltage variation of the system instead of being 4.5 volts, becomes the sum of 1.5 volts and 0.25 volt and hence 1.75 volts, resulting in a total voltage variation of only about 1.2% of the total voltage of 150 volts oftthe circuits ll--l2. Thus the performance of the system and apparatus is vastly improved with respect to the voltage sensitivity of the system including winding l0 and resistor R, a relatively small voltage variation resulting in a large chance in current ofenergization.

The resistance material having the abovementioned novel characteristics I may employ in various ways; forexample, I may embody it in the form in which the resistors shown, relating it to appropriate masses of appropriate thermal let these resistances takeother forms, relying upon the negative resistance coefiicients of temperature and include in the circuit of the corresponding resistor device R and winding it an additional resistor'made up of a non-linear impedance characteristic; in Figure l I have diagrammatically indicated at 55 how the resistor of this material may be thus included in the system and apparatus.-' In such case I am enabled to reduce the size and thermal capacity of the resistor R due to the, coasting effect of the resistor 55. In such case also I may dispense in the resistor device R with a resistor having a nega thoroughly practical advantages, are successfully tive temperature coefflcient oi resistance and use a resistance of zero temperature coemcient, re-,

sistance material of non-linear impedance characteristic has also a negative temperature coeflicient of resistance.

Thus it will be seen that there has been provided in this invention. an apparatus in which the objects above-mentioned, together with many achieyed. It will thus be seen that the invention is of a thoroughly practical character, and is in action dependably precise, and is, moreover, well adapted to meet the varying conditions met with in practice.

As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth, or shown in the accompanying drawing, is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a system of electric regulation within an electric circuit wherein a translating device, having certain predetermined internal and external physical characteristics and having certain predetermined thermal capacity and certain predetermined heat radiating surface, has the characteristic that its impedance changes with changes in operating temperature, a compensating impedance unit having internal and external physical characteristics and thermal capacity and heat radiating surface similar, to the corresponding characteristics of the translating device, and having an impedance which varies as the temperature changes in a manner to compensate for changes in the impedance of the translating de= vice, said compensating unit having a main body and a plurality of fln-like elements extendingtherefrom.

2. In a system of electric regulation within an electric circuit wherein a translating device, having certain predetermined internal and external physical characteristics and having certain predetermined thermal capacity and certain predetermined heat radiating surface,has the characteristic that its impedance changes with changes in operating temperature, a compensating impedance unit having internal and external physical characteristics and thermal capacity and heat radiating surface similar to the corresponding characteristics of the translating device, and

having an impedance which varies as the temperature changes in a manner to compensate for changes in the impedance of the translating device, said compensating unit having a main body with an opening therein to increase the rate of dissipation of heat and with insulating material thereon to retard the disssipation of heat.

3. In a system of electric regulation within an electric circuit wherein a translating device, having certain predetermined internal and external physical characteristics and having certain predetermined thermal capacity and certain predetermined heat radiating surface, has the characteristic that its impedance changes with changes in operating temperature, a compensating impedance unit having internal and external physical characteristics and thermal capacity and heat radiating surface similar to the corresponding characteristics of the translating device, and having an impedance which varies as the temperature changes in a manner to compensate for changes in the impedance of the translating device, said compensating unit having a main body with an opening therein and a plurality of finlike elements extending therefrom and with insulating material thereon.

FRANK w. GODSEY, on. 

